242 INDEX. 



right in alleging the absolute identity of substances such as 

 albumen, or fibrine, whether they occur in the animal or 

 vegetable economies. But I do not choose to assume this 

 identity in my nomenclature. It may, perhaps, be very fine 

 and very instructive to inform the pupils preparing for com- 

 petitive examination that the main element of Milk is Milkine, 

 and of Cheese, Cheesine. But for the practical purposes of 

 life, all that I think it necessary for the pupil to know is that 

 in order to get either milk or cheese, he must address himself 

 to a Cow, and not to a Pump ; and that what a chemist can 

 produce for him out of dandelions or cocoanuts, however 

 milky or cheesy it may look, may more safely be called by 

 some name of its own. 



This distinctness of language becomes every day more desir- 

 able, in the face of the refinements of chemical art which now 

 enable the ingenious confectioner to meet the demands of an 

 unscientific person for (suppose) a lemon drop, with a mixture 

 of nitric acid, sulphur, and stewed bones. It is better, what- 

 ever the chemical identity of the products may be, that each 

 should receive a distinctive epithet, and be asked for and sup- 

 plied, in vulgar English, and vulgar probity, either as essence 

 of lemons, or skeletons. 



I intend, therefore, and believe that the practice will be 

 found both wise and convenient, to separate in all my works 

 on natural history the terms used for vegetable products from 

 those used for animal or mineral ones, whatever may be their 

 chemical identity, or resemblance in aspect. I do not mean 

 to talk of fat in seeds, nor of flour in eggs, nor of milk in 

 rocks. Pace my prelatical friends, I mean to use the word 

 ' Alb ' for vegetable albumen ; and although I cannot without 

 pedantry avoid using sometimes the word * milky ' of the white 

 juices of plants, I must beg the reader to remain unaffected 

 in his conviction that there is a vital difference between liquids 

 that coagulate into butter, or congeal into India-rubber. Oil, 

 when used simply, will always mean a vegetable product ; and 

 when I have occasion to speak of petroleum, tallow, or blub- 

 ber, I shall generally call these substances by their right 

 names. 



